The invention relates to an anchor for laminated glass and a method for its setting in laminated glass in an undercut hole. The anchor is intended for fixing in laminated glass, composed of at least two layers (for instance, a support layer and an external layer), and for glazing units composed of the aforementioned set constituting a support element, a glazing cavity and an external front plate. It will be evident and understandable for a person skilled in the art that the aforementioned anchor and method for its setting may be applied also in case of other materials.
Methods for setting of anchors in laminated glass are known in the art. One of these methods consists in setting of a countersunk cap even before the lamination process. Then, a set of two glass panels with the cap set between them is laminated in a furnace under negative pressure. The connected panels have a cap set, and the cap cannot be removed. The process has some disadvantages, because during lamination at higher temperatures, the cap settles asymmetrically and askew in relation to the surface of the panels. Moreover, stresses occur resulting from the presence of the countersunk cap during the lamination process.
Other known methods for setting of the anchor in laminated glass consist in setting of a countersunk anchor in the mass of the material, not in the space between the panels. In one of these methods, the anchor is set in a conical hole with an undercut in the glass panel's depth. It is an analogous method with that used in the case of anchors for stone. The hole is not made all the way through. Then, the anchor with a protruding threaded mandrel is installed in the hole using a special machine. In another variant of this method, the anchor is set in a prepared hole, but the gap formed between the anchor and the hole requires filling with a sealant. The sealant is fed via a special hole in the anchor's sleeve.
Methods for fixing of glass using a rotule fitting are also known, and they require making a through-hole, penetrating all layers of glass. In such case, the glass panels are fixed in a visible way. The fixations of rotule fittings may be set even with the surface of the exterior wall finish or as protruding. Another method consists in cementing of steel elements using silicones for glass.
From Polish patent description No. PL166087, a coupling is known, having a spacing element in the form of a two-way bent, oval metal ring. Its bent ends abut the conical surface of the coating of the spacing cone. The front panel is characterised in that the ring is pushed onto the spacing cone, and in the undercut, its external edge abuts the wall of the drilled hole.
From another Polish patent description No. PL202352, a system with a fixing element anchored in a plate composite casing is known. The fixing element anchored in an undercut hole has an expansion cone, onto which an expansion ring is pushed. In order to enable alignment of the shift between the layers of the composite casing, the hole in the external layer has a larger diameter than that in the next layer of the composite casing. Moreover, the washer of the fixing element has an injection hole that enables filling the space between the threaded mandrel of the fixing element and the wall of the hole in the external layer of the composite casing with a sealant. A disadvantage of this solution consists in the fact that it requires using a sealant, and the anchor protrudes beyond the surface of the material.
From German paten application No. DE102009044770, an anchor set in laminated glass in a conical hole with an undercut is known. Such setting of the anchor requires making a hole in the depth of one glass panel and a through-hole in the other panel. The anchor is set using an expansion element for a countersunk cap with two sealing layers which may shift in relation to one another. A disadvantage of this solution consists in the fact that it requires using washers.
Next, in European patent No. EP1660737, a fixing device is disclosed for creation of anchorage in panels made of monolithic glass. It requires using a cover made of a flexible material and a hardenable mix on the mandrel.